Gas turbine engines include a starter motor electrically coupled to a variable frequency drive electrically connected to an alternating current (AC) power source. The AC power source is also electrically connected to other variable frequency drives electrically coupled to motors driving pumps, ventilation fans, and/or coolers of subsystems of the gas turbine engine. However, the AC power source may fail or become interrupted.
U.S. Pat. No. 7,250,688 to Scott Thomson et al. discloses a starter/generator system for a gas turbine engine used in aeronautical applications. In a starting mode, the starter/generator system couples a single dynamoelectric machine to the gas turbine engine through a torque converter in a starting mode. In a generating mode, the starter/generator system engages the engine to the dynamoelectric machine through a mechanical differential after the engine reaches self-sustaining speed. The starter/generator system combines the output of the engine and the torque converter to regulate the frequency of AC generated by the dynamoelectric machine within a range of frequencies suitable for on-board electrical equipment by dynamically regulating the flow of hydraulic fluid to the torque converter.
The present disclosure is directed toward overcoming one or more of the problems discovered by the inventors.